1. Field of the Invention
The present invention relates to a semiconductor device provided with a power supply ring to provide a power supply to an internal circuit.
2. Description of the Related Art
Conventionally, in some semiconductor devices such as an LSI, a ring-shaped wiring called a power supply ring is provided therein to supply a power supply from outside to an internal circuit. In the semiconductor device provided with the power supply ring, a pad for a power supply connected to an external power supply (power supply terminal) (or a power supply wiring connected to this pad) and the power supply ring are connected by vias (through-hole contacts), and the power supply ring and the internal circuit (in more detail, the power supply wiring in the internal circuit) are connected by vias and wirings as required. Therefore, the power supply from outside supplied to the pad for the power supply is supplied to the power supply ring through the vias, and further supplied to the internal circuit from the power supply ring (See Patent Document 1, for example).
Further, in the semiconductor device, to improve the degree of circuit integration, wiring width and so on in the semiconductor device are made smaller year by year, and the pad pitch (distance between adjacent pads) correspondingly becomes narrower. Furthermore, to reduce the size of a chip, the structure of “a pad above I/O” in which a pad is disposed above an input/output circuit (I/O) is used as necessary.
(Patent Document 1)
Japanese Patent Application Laid-open No. 2000-307063